<!DOCTYPE html> <html class="reftest-wait"> <link id="e" href="data:text/css,.ref { background-color: green; }" rel="stylesheet"> <script> function boom() { document.documentElement.appendChild(document.getElementById("e")); document.styleSheets[0].cssRules[0]; // Remove reftest-wait async so we give the SheetComplete a chance to run setTimeout(function() { document.documentElement.className = ""; }, 0); } </script> <body onload="boom();"></body> </html>